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In this picture you can see a
deity statue decked in red clothing.
In Japan, the color red is associated with a few deities in Shinto and Buddhist traditions.
According to Japanese folk belief, red is the color for expelling demons and illness.

It seems that the association of red with diseases comes from the
first cases of smallpox in the eighth century, when in the worst cases the skin turned red.
Soon after that the red color was associated with life creating and life sustaining deities. Since then, the color red has been dedicated not only to deities of sickness, but also to deities of healing, fertility, and childbirth.